TY - JOUR
T1 - Superconducting scanning tunneling microscopy tips in a magnetic field
T2 - Geometry-controlled order of the phase transition
AU - Eltschka, Matthias
AU - Jäck, Berthold
AU - Assig, Maximilian
AU - Kondrashov, Oleg V.
AU - Skvortsov, Mikhail A.
AU - Etzkorn, Markus
AU - Ast, Christian R.
AU - Kern, Klaus
N1 - Publisher Copyright:
© 2015 AIP Publishing LLC.
PY - 2015/9/21
Y1 - 2015/9/21
N2 - The properties of geometrically confined superconductors significantly differ from their bulk counterparts. Here, we demonstrate the geometrical impact for superconducting scanning tunneling microscopy (STM) tips, where the confinement ranges from the atomic to the mesoscopic scale. To this end, we compare the experimentally determined magnetic field dependence for several vanadium tips to microscopic calculations based on the Usadel equation. For our theoretical model of a superconducting cone, we find a direct correlation between the geometry and the order of the superconducting phase transition. Increasing the opening angle of the cone changes the phase transition from first to second order. Comparing our experimental findings to the theory reveals first and second order quantum phase transitions in the vanadium STM tips. In addition, the theory also explains experimentally observed broadening effects by the specific tip geometry.
AB - The properties of geometrically confined superconductors significantly differ from their bulk counterparts. Here, we demonstrate the geometrical impact for superconducting scanning tunneling microscopy (STM) tips, where the confinement ranges from the atomic to the mesoscopic scale. To this end, we compare the experimentally determined magnetic field dependence for several vanadium tips to microscopic calculations based on the Usadel equation. For our theoretical model of a superconducting cone, we find a direct correlation between the geometry and the order of the superconducting phase transition. Increasing the opening angle of the cone changes the phase transition from first to second order. Comparing our experimental findings to the theory reveals first and second order quantum phase transitions in the vanadium STM tips. In addition, the theory also explains experimentally observed broadening effects by the specific tip geometry.
UR - https://www.webofscience.com/wos/woscc/full-record/WOS:000361832600041
UR - https://openalex.org/W1799378078
UR - https://www.scopus.com/pages/publications/84942546530
U2 - 10.1063/1.4931359
DO - 10.1063/1.4931359
M3 - Journal Article
SN - 0003-6951
VL - 107
JO - Applied Physics Letters
JF - Applied Physics Letters
IS - 12
M1 - 122601
ER -